Seating

People dont seat themselves efficiently with open seating. Groups can be split up from each other very easily and you'll need extra seating to accommodate that. Just a heads up.

In general having open seating means you will need more tables and chairs as people will spread out, so if you need to pay for rental tables and chairs (linens, centerpieces,dishes) you should think about budget first on this one, all that adds up!
Then a lot of people will caution that yes this tends to leave the more socially anxious and reserved in an awkward position, if it's cold and people have coats or guests set their things down people might be tempted to move the things. People are odd like that.
Also because of the size of your wedding most people will likely expect a seating chart of some sort and they might get distracted or start milling around at the entrance of where ever you're having the reception without that sense of direction.
That being said you can do people at a general table instead of picking exact seats. It's often much easier to say 8 people per table amd pick 8 people than it is to place individual seats.

It is totally fine to do open seating. My sister had open seating for her wedding and it worked fine. She did have additional chairs (maybe 15 extra) and I plan on doing the same as well.
If you’re having a plated meal, that would be my only reasoning for having a seating chart or if it’s black tie.

This sign is intended for the ceremony, not the reception. Traditionally people seat themselves on the side of the ceremony venue where the person they’re closest to will be standing during the ceremony.

Keep in mind how you’re feeling not knowing where to seat people, that’s how all of your guests will feel when they’re trying to find a spot for them and their dates or families to fit. It really is so much more considerate to your friends and family to at least assign tables. Also, as Chandra mentioned, you will need to provide 20% more seating, tables, and center pieces if you do open seating since guests won’t seat themselves efficiently - which can get expensive.

I think everyone brings up good points here. I also think that there are certain people you will want to keep together and without assigned tables that might not happen. You may also want certain groups closer to your head table and some further away. I just think assigned tables make everything run smoother but it can work without them. Just might be a bit mores stressful on your guests.

We're doing open seating. It's going to be buffet style dinner. We plan on reserving a couple of tables for family and have 2 extra tables for overflow. I don't want to go through the aggregation of a seating chart.
I would strongly recommend a seating chart for plated service however.

Just a little plug for doing a seating chart: my fiancé and I have 110 guests coming to our wedding and we did our seating chart yesterday in about a half hour. It really wasn’t that hard. I think assigning tables is really helpful just to take some stress off guests so they don’t have that anxious, high school cafeteria moment of “where am I gonna sit?” or so that they don’t end up with total strangers or dragging extra chairs to cram into tables so they can sit with their partners or friends.

If you were going under 50 people, I would say open seating is fine. With a large wedding like you will have, definitely do the seating arrangements so that groups aren’t split up. Say you have a group of 4 or 5 that come in last but there are only single seats left at scattered tables. It’s fairly easy to group your family and friends in general circles, aunts and uncles at one, cousins at one, coworkers at another etc.

I've been to a wedding where there wasn't a seating chart and I ended up sitting by myself. Left after an hour because I felt uncomfortable.

What happened was people dragged chairs to the tables that already were full and just sat with whomever they wanted. The table I ended up at had seating for 8 but there was only 4 chairs because people moved them.

I know it sounds like an easy fix, and it is if you do it for the ceremony itself, but for the reception having people choose their tables can really lead to even more awkwardness.

Seating charts aren't hard. Divide the people into groups then go from there. Family members, friends, work friends, etc brides/grooms. Then put them at tables with people they already associate with.

I've only been to two weddings with open seating and both were a bit chaotic. At one a couple got upset that there weren't enough seats at our table, so our group was split. At the other, one of the groomsmen's fiance didn't know anybody but the wedding party and was sitting by herself; Luckily I had met her a few times and we had her sit with us, but it was very awkward for her when she didn't know who to sit with. If you're having a wedding where everyone knows a lot of people and seating options wouldn't be a problem for anyone, open seating can work! If not, it can make some people uncomfortable.

The seating chart is for the reception. The sign you are showing us is for the ceremony. I've never heard of anyone doing a chart for the ceremony. There's Bride's side, Groom's side, or something like the sign indicates above. But for the reception, guests don't seat themselves efficiently at all. This is why you need to at least assign tables. Otherwise, you're going to have big gaps in some tables, families will be split up because they won't be able to find seating with their loved ones, total mess. Also, if you don't do a chart for the reception, you'll have to make sure you have at least 25% more seating at your venue (which could cost you $$&dollar, because of the inefficient way people seat themselves.

Please, I implore you to assign tables (you do not have to assign seats). It can be painful for people to walk into the room and look for seat, find one, and be told, sorry, we are saving. Groups get separated. People who you wanted to have nice seats, are stuck in the back, etc. And rest assured, when people tell you the guests are happy with no assigned tables, most are not, they are just too polite to say anything.